The development of a model to describe the influence of temperature and relative humidity on respiration rate of prickly pear cactus stems in reduced O2 conditions

Respiration rate (RO2) of prickly pear cactus stems (Opuntia spp.) was measured as a function of 4 temperature (T) and 6 relative humidity (RH) combinations for O2 partial pressures between 15 and 0.8 kPa, which were considered to support aerobic respiration. The rate of respiration (RO2) was determined based on O2 depletion of the atmosphere in sealed containers containing 1 kg of stems. The O2 partial pressure declined linearly over time and the slopes of the fitted lines were used to calculate the rate of O2 uptake. The rate of O2 uptake increased with increasing temperature and decreased with increasing RH. The respiratory rate at 25°C was approximately 30 to 40 times higher than at 5°C. The respiratory rate at 65% RH was between 30 and 90% greater than at 90% RH, depending on the temperature. Data for ln(RO2) for each RH level were regressed against the inverse of the T (K-1) to determine Arrhenius constants and calculate the apparent Ea of respiration for the six RH conditions. The Ea was similar for each RH level, varying between a low of 113 to a high of 131 kJ•mol-1. An equation having an R2 of 0.95 was developed describing respiration as a function of RH and T (°C) using only four constant

Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity

Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var. cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4). All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3 also accepts a wide range of substrates but with very strong preference for producing benzyl acetate. Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating 268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the multiplicity of AAT genes accounts for the great diversity of esters formed in melon

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

The Psychological Science Accelerator’s COVID-19 rapid-response dataset

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

The Psychological Science Accelerator’s COVID-19 rapid-response dataset

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

Chemical composition and inheritance patterns of Aroma in Fragaria x ananassa and Fragaria virginiana progenies

Carrasco, B. Centro de Investigación en Biotecnología Silvoagrícola, 2 Instituto de Biología Vegetal y Biotecnología, Universidad de Talca, Casilla 721, Talca, Chile. E-mail [email protected], J.B. Facultad de Ciencias Agrarias and Centro de Investigación en Biotecnología Silvoagrícola, Universidad de Talca, Casilla 747, Talca, ChileThe strawberry aroma is one of the most popular fruit flavors (Bood and Zabetakis, 2002); its chemical composition has been extensively studied (Mc Fadden et al., 1965; Pérez et al., 2002; Schreier, 1980). To date, over 300 different aromatic compounds have been identified (Latrasse, 1991; Zabetakis and Holden, 1997). Among them, esters and furanones are considered the main aroma determinants in fresh strawberries. Although aroma is a highly appreciated organoleptic attribute, studies to determine the genetic basis of strawberry aroma are scarce (Aharoni et al., 2000). They have been focused on identifying some specific genes, but little is known about the inheritance patterns of the aroma trait and the main compounds associated with it. The objective of this study was to determine the nature of aroma inheritance in segregating populations of strawberries and identify the most important aroma component

Quality of 'Ivanhoe' and 'Bluecrop' blueberry fruit transported by air and sea from Chile to North America

Claudia E. Moggia and Jorge B. Retamales. Escuela de Agronomía, Universidad de Talca, Casilla 747, Talca, Chile.We assessed the influence of fruit maturity (percent blue coloration), shipping mode [plane (air) vs. boat (sea)], and storage method [refrigerated air (RA) vs. controlled-atmosphere (CA)] on highbush blueberry (Vaccinium corymbosum L.) quality. Fruit picked when 60% blue had lower soluble solids (SS), higher titratable acidity (TA), and a lower SS: TA ratio than 100% blue fruit both before and after 15 days of storage at 2 °C. They were also firmer and had better internal condition. Fruit shipped by sea to North America had poorer internal condition, were less firm, had fewer sound fruit, and lost more water than those arriving by air and stored for the duration of the sea shipment. CA storage (2 kPa O2 and 8 kPa CO2, 0 °C, 21 days) of fruit shipped by air did not enhance fruit quality in comparison with RA storage (ambient O2 and CO2, 0 °C, 21 days) except by minimizing mass loss. After an additional holding period (20 °C, 3 days) to simulate nonrefrigerated retail conditions, CA-stored fruit had less decay than RA-stored fruit. Maintaining low temperature during the holding period after CA or RA storage was critical in preventing decay, especially for the `Ivanhoe', which was more susceptible to decay, softening, and internal breakdown than `Bluecrop' across all treatments